I work for a very large fortune 500 company. In order to improve the development process, I would like to allow employees to wireframe using components that already have the companies' brand and look and feel, as opposed to apply graphic design after finishing the wireframes (or detailed design) or use graphic guidelines only when development starts. Although there are disadvantages to do colorful and highly detailed wireframes, I believe this will shorten the graphic design phase.
I considered iRise annd Axure but they are too complex to learn for people who are developers, system analysts and projects managers, not UX professionals. Other popular tools like UXPin, Mockflow and others do not support customizing components for re-use.
What wireframing/prototyping tool would you recommend that supports this need? It must have a quick learning curve, customizable UI components library and real time collaboration.